interface Com {
  int add(int a,int b);
}
abstract class A6_2{
  abstract int add(int a,int b);
}
class B6_2 extends A6_2 implements Com {
  public int add(int a,int b) {
    return a+b;
  }
}
public class E6_2 {
  public static void main (String args[]){
    B6_2 b=new B6_2();
    Com com=b;
    System.out.println(com.add(12,6));
    A6_2 a=b;
    System.out.println(a.add(10,5));
  }
}
